According the National Institutes of Health, there are more than 800,000 strokes each year in the U.S. A stroke occurs when the blood supply to part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients. Within minutes, brain cells begin to die. Stroke, which is the fourth leading cause of death in the U.S., causes more serious long-term disabilities than any other disease. May is National Stroke Awareness Month, an effort to educate the public about stroke risk factors and the importance of acting quickly when a stroke occurs.